fix(runtime): swap plugin cache links atomically - #134
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NagyVikt merged 2 commits intoAug 7, 2026
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August 7, 2026 12:27
A Stop hook died mid-session with "Plugin directory does not exist: <runtime>/plugins/cache/thedotmack/claude-mem/13.13.1 — run /plugin to reinstall". The plugin was not missing: its payload had been on disk since 2026-08-04, and only the runtime's `plugins/cache` symlink was gone, recreated ten seconds later while hooks were firing. linkPluginCache replaced each entry with rm() then symlink(). Between those two awaits the path does not exist, and runtimes are re-materialized while sessions are live — so a hook resolving a plugin installPath in that window hits the exact error this function's doc comment says it prevents. Stage the new link beside the target and rename() it over instead. rename(2) within one directory is atomic, so a concurrent reader sees the old entry or the new one, never neither. rename refuses to clobber a real directory, so remove-then-create stays as the fallback for Claude's lazy empty cache/ copy on a first materialization — no session can be reading it yet. On failure the staged link is cleaned up and the existing entry is left alone. The window was not theoretical. The new race test polls the path across 300 swaps: 441 ENOENTs against the old implementation, 0 against this one. It cannot false-fail, since an atomic rename has no window in which the entry is absent.
The fallback branch can't be atomic — POSIX has no way to replace a directory with a symlink in one step. Say so, instead of claiming no session can be reading it.
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AI review (gate): no CRITICAL/HIGH. One finding, fixed in
Validation:
The race assertion is the load-bearing test: polling the target across 300 swaps yields 441 ENOENT against the old rm-then-symlink implementation and 0 against this one. Verified by reverting the implementation and re-running. |
NagyVikt
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August 7, 2026 10:31
NagyVikt
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August 7, 2026 10:31
This was referenced Aug 7, 2026
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Summary
Test plan